I. Field
The following description relates generally to wireless communications, and more particularly to providing Quality of Service (QoS) continuity in connection with a mobility procedure in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data can be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources (e.g., bandwidth, transmit power, . . . ). For instance, a system can use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple access terminals. Each access terminal can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to access terminals, and the reverse link (or uplink) refers to the communication link from access terminals to base stations. This communication link can be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.
MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas can be decomposed into NS independent channels, which can be referred to as spatial channels, where NS≦{NT, NR}. Each of the NS independent channels corresponds to a dimension. Moreover, MIMO systems can provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and receive antennas are utilized.
MIMO systems can support various duplexing techniques to divide forward and reverse link communications over a common physical medium. For instance, frequency division duplex (FDD) systems can utilize disparate frequency regions for forward and reverse link communications. Further, in time division duplex (TDD) systems, forward and reverse link communications can employ a common frequency region so that the reciprocity principle allows estimation of the forward link channel from reverse link channel.
Wireless communication systems oftentimes employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to an access terminal. An access terminal within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, an access terminal can transmit data to the base station or another access terminal.
As part of a typical Quality of Service (QoS) model, a central node within a core network oftentimes manages a subset of parameters related to QoS. The central node, for instance, can be a Packet Data Network Gateway (PDN GW). The PDN GW can provide a description parameter to a serving base station that indicates a type of traffic (e.g., uplink and/or downlink traffic) to be transferred between two endpoints (e.g., between the PDN GW and an access terminal, . . . ) through one or more intermediate nodes (e.g., the serving base station, Serving Gateway (S-GW), . . . ). For instance, the description parameter can be a QoS Class Index (QCI) that describes the type of traffic (e.g., voice, streaming video, . . . ). The serving base station can receive and utilize the description parameter to identify the traffic type, and can initialize and/or control a disparate subset of parameters related to QoS (e.g., Layer 2 (L2) parameters, logical channel priority, Prioritized Bit Rate (PBR), Maximum Bit Rate (MBR), Guaranteed Bit Rate (GBR), . . . ).
Due to the mobile nature of access terminals in general, an access terminal can move from being under coverage of a first base station (e.g., source base station, . . . ) to a second base station (e.g., target base station, . . . ). Accordingly, a mobility procedure (e.g., handover, handoff, . . . ) can be effectuated such that the access terminal transitions from being served by a source base station to being served by a target base station. Conventional mobility procedures, however, typically fail to transfer the subset of QoS parameters set by the source base station to the target base station. When employing mobility procedures, the target base station can be provided with the description parameter from the PDN GW, and thus, can identify the type of traffic. Yet, the target base station commonly reconstructs the disparate subset of parameters related to QoS (e.g., previously built by the source base station, . . . ) since such parameters typically fail to be transferred to the target base station from the source base station (e.g., in connection with inter-base station handover, . . . ), which can lead to disruption in traffic, increased exchange of signaling messages over the air, and the like.